NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.: Physics MCQs (Practice_Test 21 of 35)
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- A single slit is used to observe diffraction pattern with red light. On replacing the red light with violet light the diffraction pattern would be
- remain unchanged
- become narrower
- become broader
- disappear
- The thickness of a quarter-wave plate made of quartz for wavelength l = 5000 A, refractive indices mE = 1.553 and m0 = 1.543 is
- 5.00 × 10 − 3 cm
- 3.75 × 10 − 3 cm
- 2.50 × 10 − 3 cm
- 1.25 × 10 − 3 cm
- When unpolarised light gets reflected from a plane glass surface, it becomes partly polarized because glass
- is optically active
- rotates the components in the plane of incidence and those perpendicular to the plane of incidence by different amounts
- reflects the components of light parallel to the plane of incidence and those perpendicular to it by different amounts
- is a stereoisomer
- If a quarter wave-plate with its fast axis vertical is inserted into abeam of linearly polarized light oscillating at 450, then the emerging light will be
- linearly polarized
- vertically polarized
- left circularly polarized
- left elliptically polarized
- In a Fabry-Perot interferometer the circular fringes formed are referred to as fringes of
- equal thickness
- equal inclination
- equal chromatic order
- None of the above
- Scattering intensity of pure carbon tetrachloride is 6 units for 500. The scattering intensity for 4000 is
- 4.5 units
- 6.0 units
- 7.5 units
- 14.6 units
- A substance shows a Raman frequency shift of 4000 cm-1. If this mode is active in the infra-red, then the corresponding infrared adsorption band will be at
- 0.5 m
- 1.0 m
- 1.5 m
- 2.5 m
- The population inversion necessary for laser action used in solid state lasers is
- electrical discharge
- inelastic atom-atom collision
- direct conversion
- optical pumping
- A given amount of heat cannot be completely converted into work. How ever it is possible to convert a given amount of work completely into heat. This apparently contradictory statement results from the
- zero th law of thermodynamics
- first law of thermodynamics
- second law of thermodynamics
- third law of thermodynamics
- The work done, W, during as isothermal process in which the gas expands from an initial volume V1 to a final volume V2 is given by (R: Gas constant, T: Temperature)
- R (V2 − V1) loge (T1⟋T2)
- R (T2 − T1) loge (V1⟋V2)
- R T loge (V2⟋V1)
- 2 R T loge (V1⟋V2)
- The combined form of first and second law of thermodynamics is given by (P: Pressure V: Volume, T: Temperature, U: Internal energy, S: Entropy, Q: Quantity of heat)
- TdS = dU + PdV
- dQ = TdS + PdV
- dU = TdS + dQ
- TdS = dU-PdV
- The temperature of water (mass, m) increases from T1 to T2. If C is the specific heat capacity of water, then the total increase in entropy of water is given by
- mC (T2 − T1)
- MC loge T1⟋T2
- mC (T1 − T2)
- mC loge T2⟋T1
- Which one of the following Maxwell՚s relations leads to Clausius-Clapeyron equation?
- (T⟋V) S =- (p⟋S) V
- (T⟋P) S = (V⟋S) P
- (V⟋T) P =- (S⟋P) T
- (S⟋V) T = (P⟋T) V
- A perfect gas at 27 degree C is heated at constant pressure so as to doubles its volume. The temperature of the gas will now be
- 600 degree C
- 327 degree C
- 300 degree C
- 54 degree C
- Consider the following processes that take place in a Carnet cycle:
- Adiabatic expansion
- Adiabatic compression
- Isothermal expansion
- Isothermal compression
- The correct sequence of the above process is
- 1,3, 4,2
- 3,1, 2,4
- 3,1, 4,2
- 1,3, 2,4